1. Field of the Invention
This invention relates to a pocket separator for electric storage battery plates.
2. Description of the Prior Art
Various structures have been proposed for pocket separators for electric storage batteries, and particularly for the lead acid type of battery. Such pocket separators are intended to envelop the battery plates for separation of the positive and negative plates. Prior art separator pockets have consisted of a porous sheet of synthetic resin, which was folded and sealed to form a pocket open at the top and closed at the bottom and sides. An electrode plate such as a positive electrode plate for lead acid batteries was inserted into the pocket, with a plurality of pockets and interposed negative plates assembled to form cells.
It has been found that using separator material with smooth inner surfaces which faced the electrode plate were subject to deterioration during use, and to puncturing from warped negative plates which wore holes in the pocket until the plates touched and shorted out the battery.
One solution has been to provide the inner surfaces of the pocket with a plurality of vertical ribs, but this and other rib configurations such as slanted ribs did not allow for free gas flow. It has also been proposed, as shown in the European Patent, to Nakano et al No. EP0541124A2, to provide the separator material which forms the pockets, with a plurality of parallel, vertical widthwise spaced ribs in the middle, and a plurality of intersecting vertically spaced ribs on the widthwise left and right sides, and portions of the facing surfaces, and also at the intersecting front and rear corner edge portions. While this structure is an improvement over prior structures, it is not satisfactory for enveloped negative plates, since during the alignment process, when using enveloped negative plates, the vertical ribs of the separator "catch" the edge of the positive plates causing misalignments and slow production.
The pocket separator of the invention is suitable for both positive and negative plates, does not suffer from the prior art problems and provides positive advantages.